Pharmaceutical and cosmetic products and perfume dispensers generally comprise a pump mounted on a container and activated by a push-button so as to deliver the product.
When the delivery is completed, it is necessary to equalize the loss of the discharged product volume with an equivalent volume of air which is taken from the outside, because of the depression inside the container. This air intake is automatically carried out first through the passages provided therefor inside the pump body, then via a so-called vent orifice provided through the body wall and opening inside the container. The pressure inside the container thus remains identical to that of the atmosphere outside.
However, it is necessary to provide for the filtration of the incoming air flow, if only to preserve the proprieties of the product and prevent the risks of pollution or bacterial or fungal contamination, more particularly for the packaging of pharmaceutical or cosmetic products.
The existing filtration devices are generally composed of a ring made of a filtering material mounted with a radial tightening around the pump body and covering the vent orifice.
However, this solution is not satisfactory since the ring increases the outer diameter of the pump body which involves assembling problems in the container neck and tightness problems.
Besides, the mechanical resistance of this ring is not reliable over time, which entails risks of accidental pollution. As a matter of fact, the contact area between the pump body and the filter must be perfectly air tight, so as to force it through the ring.
In addition, an excessive tightening of the ring on the pump body may entail malfunctions of the later.